Technical Abstract:
Current methods of preventing outbreaks of avian coccidiosis involve medication of feed with ionophore drugs or synthetic chemicals or by vaccination of chicks with low doses of Eimeria oocysts in ovo or by spray vaccination just after hatch. Our data indicates that the uniformity and efficiency of vaccination can be improved such that each chick receives a dose of Eimeria oocysts sufficient to induce immunity during early growout. Our battery pen studies have shown that applying gel beads containing Eimeria oocysts to starter feed increases vaccine coverage, equivalent to oral gavage of individual chicks. In the present study, day-old chicks were placed in floor pens after being immunized with a mixture of Eimeria oocysts delivered by a different vaccination method (oral gavage, spray vaccination, or gel beads). At 4 weeks of age, chickens (and non-immunized controls) were challenged with a high dose of Eimeria oocysts. Chicks vaccinated by either gel bead or oral gavage displayed complete protection (P < 0.05) against challenge compared to controls as measured by weight gain over the infection period. Chicks immunized by spray administration showed no significant (P > 0.05) weight gain protection. No significant difference (P > 0.05) was observed in FCR between groups vaccinated by any of the oocyst delivery methods. These findings indicate that gel bead technology is a viable alternative for administering Eimeria oocysts to day-old broiler chicks under poultry house conditions that allow for cycling of oocysts from litter. More practical delivery methods of spraying gel beads onto feed are being explored.